This invention is based on and claims priority to Japanese Patent Application Nos. 20000-77084 and 2001-029961, filed Mar. 17, 2000 and Feb. 6, 2001, respectively, the entire contents of which are hereby expressly incorporated by reference.
1. Field of the Invention
This invention relates to a control system for an engine of a watercraft.
2. Description of Related Art
Personal watercraft have become very popular in recent years. This type of watercraft is quite sporting in nature and carries one or more riders. A hull of the personal watercraft commonly defines a rider""s area above an engine compartment. An internal combustion engine powers a jet propulsion unit that propels the watercraft by discharging water rearward. The engine lies within the engine compartment in front of a tunnel, which is formed on an underside of the hull. The jet propulsion unit is placed within the tunnel and includes an impeller that is driven by the engine.
A deflector or steering nozzle is mounted on a rear end of the jet propulsion unit for steering the watercraft. A steering mast with a handlebar is linked with the deflector through a linkage. The steering mast extends upwardly in front of the rider""s area. The rider remotely steers the watercraft using the handlebar.
The engine typically includes a throttle valve disposed in an air intake passage of the engine. The throttle valve regulates an air amount supplied to the engine. Typically, as the amount of air increases, the engine output also increases. A throttle lever or control is attached to the handlebar and is linked with the throttle valve usually through a throttle linkage and cable. The rider thus can control the throttle valve remotely by operating the throttle lever on the handlebar.
When docking, the rider operates the handlebar to make a right or left turn toward the dock. Under some conditions, the rider may have a little difficulty in slowly guiding the watercraft into a docking position. A need therefore exists for an improved engine output control for a watercraft that can enhance maneuverability of the watercraft under at least slow speed conditions.
In accordance with one aspect of the present invention, a watercraft comprises a water propulsion device and an engine powering the water propulsion device. An engine output control mechanism is arranged to control the engine""s output. A steering mechanism is arranged to the watercraft. A first sensor is arranged to sense a state of the engine output control mechanism. A second sensor is arranged to sense a state of the steering mechanism. A control device is configured to control the engine output control mechanism based upon a first control parameter corresponding to an output of the first sensor and a second control parameter corresponding to an output of the second sensor. The control device causes the engine output control mechanism to increase the engine output when the first control parameter is less than a first reference magnitude and the second control parameter is greater than a second reference magnitude.
In accordance with another aspect of the present invention, a watercraft comprises a water propulsion device and an engine powering the water propulsion device. An engine output control mechanism is arranged to control the engine""s output. A steering mechanism is arranged to steer the watercraft. A first sensor is arranged to sense a state of the steering mechanism. A second sensor is arranged to sense a velocity of the watercraft. A control device is configured to control the engine output control mechanism based upon a first control parameter corresponding to an output of the first sensor and a second control parameter corresponding to an output of the second sensor. The control device causes the engine output control mechanism to increase the engine output when the first control parameter is greater than a first reference magnitude and the second control parameter is greater than a second reference magnitude.
In accordance with a further aspect of the present invention, a watercraft comprises a water propulsion device and an engine powering the water propulsion device. A steering mechanism is arranged to steer a thrust direction of the water propulsion device. The thrust direction is quickly changed under a first condition when the water propulsion device produces a thrust force greater than a predetermined thrust force. Means are provided for recognizing that the steering mechanism is steered under a second condition in which the water propulsion device does not produce a thrust force greater than the predetermined thrust force. Additional means are provided for increasing an output of the engine when the recognizing means recognizes that the steering mechanism is steered under the second condition.
In accordance with a further aspect of the present invention, a watercraft comprises a water propulsion device and an engine powering the water propulsion device. The engine has at least one combustion chamber and an air induction system arranged to provide air to the combustion chamber. A throttle valve is disposed in the air induction system for regulating an amount of the air flowing into the combustion chamber. A steering assembly is arranged to steer the watercraft. A first sensor is arranged to sense an opening degree of the throttle valve. A second sensor is arranged to sense an angular position of the steering assembly. An electrically operated control device is provided. A throttle valve actuator is arranged to operate the opening degree of the throttle valve. The control device is configured to control the throttle valve actuator based upon an output of the first sensor and an output of the second sensor. The control device causes the throttle valve actuator to operate the throttle valve to increase the opening degree when the output of the first sensor indicates that the sensed opening degree less than a reference opening degree and the output of the second sensor indicates that the sensed angular position is greater than a reference angular position.
In accordance with an additional aspect of the present invention, a control method is provided for an engine of a watercraft. The watercraft has a water propulsion device, an engine output control mechanism, a steering mechanism, at least two sensors and a control device. The method comprises sensing a state of the engine output control mechanism by one sensor, sensing a state of the steering mechanism by another sensor, determining whether a first control parameter corresponding to a sensed state of the engine output is less than a first reference magnitude, determining whether a second control parameter corresponding to a sensed state of the steering mechanism is greater than a second reference magnitude, and increasing engine output by the control device if the results of both determinations are affirmative (i.e., are true).
In accordance with a still another aspect of the present invention, a control method is provided for an engine of a watercraft. The watercraft has a water propulsion device, a steering assembly, at least two sensors and a control device. The engine includes a throttle valve and a throttle valve actuator. The method comprises sensing an opening degree of the throttle valve by one sensor, sensing an angular position of the steering assembly by another sensor, determining whether the sensed opening degree is less than a reference opening degree, determining whether the sensed angular position is greater than a reference angular position, and increasing the opening degree by the control device if the results of both determinations are affirmative (i.e., are true).
Further aspects, features and advantages of this invention will become apparent from the detailed description of the preferred embodiments which follow.